[docs] [issue29866] Added datetime_diff to datetime.py.

[Decorater]

New submission from Decorater:

The datetime_diff function compares two datetime objects and returns the time since the prior datetime objects (based on the current datetime object) in a what that is readable by humans.

This is useful when one might need to compare two datetime objects, keeping ones codebase as small as possible (to ensure fast Python code), and to reduce 'hacks' in their code to make the comparison more readable by humans

the github pull request comes with changes to datetime.rst as well

Note: This is currently targeting 3.7, however if you guys desire you guys could backport it into 3.5 and 3.6.

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assignee: docs at python
components: Documentation, Library (Lib)
messages: 289917
nosy: Decorater, docs at python
priority: normal
severity: normal
status: open
title: Added datetime_diff to datetime.py.
versions: Python 3.7

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Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue29866>
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